The invention relates to tap assemblies, and more specifically to a reciprocal positioning assembly for a tap assembly.
Tap assemblies typically include a body which defines a fluid flow chamber into which at least two sleeves lead, one which is connected with an inlet and the other which is connected with an outlet, for flow of fluid. A third sleeve houses a pressure limiting means and clapper driving means. To control flow of fluid through the chamber, from the inlet toward the outlet, a clapper moves very nearly perpendicularly to a seat which is supported by the body at the lower end of a corresponding sleeve.
For the control of a tap or cock by a thermostatic feeler, the reciprocal positioning assembly is usually shaped like a rod, the end part of which penetrates into the body, and specifically into the sleeve, until, according to the temperature which has been detected, the feeler or rod has taken a position which allows the clapper to be closed, or which precludes the tap or cock from being shut.
The section of the feeler or rod is sufficiently large to resist any warping due to the force which it must exert on the clapper, without undergoing any buckling. However, the section must also be sufficiently reduced to provide an adequate passage within the sleeve through which the fluid can flow. Because of the difference between the inner diameter of the sleeve and the outer diameter of the end part of the feeler, the end part, when moved and translated, cannot be guided directly by the sleeve. The feeler, because of its length, requires a positioning means which operates with precision.
A rod positioning assembly located in a bore is well known in the art. An "elastic ring" or a "circlips" can only provide a thrust stop in an axial direction. The only positioning function it can ensure is along the axis. These "positioners" are inadequate when, in relation to the axis, a precise positioning is required on a radial plane. Neither can the positioners provide any effective guidance during a translation or transfer of the rod assembly.
The elastic ring is shaped like a radially split washer. Its outer or inner edge is then placed in the groove of a rod or a shaft. After the washer has been put into place, only one of its radial faces is operational. The other one, an inner or outer edge, is generally an irregular shape and remains free. Elastic rings shaped like wide washers are also known in the art. Because of their width, they adequately obstruct the space between the sleeve and the rod, but are insufficient to solve the guidance problem in any tap or cock assembly. This is because the washer, although it is split, would then substantially inhibit and prevent the flow. Instead of wide elastic rings in the shape of split washers, elastic positioners are known, made up with a short length of steel wire, the middle part of which is shaped like an open ring. This ring follows the outer edge of an elastic organ or part. From the edges of the ring opening, the extreme parts of the ring are pressed and folded down towards the inner zone of the ring on its level. The rings thus constitute inner branches, the ends of which are connected with the open ring, thus providing an interval or space between one and the other. Their other ends lean and are shored up, one against the other.
In addition to the lack of stability of the ring, misshaping, or material deformation, is also a problem. As a result, the ring cannot be used to position the rod in the sleeve or provide guidance during translations and transfers in a precise manner.
Accordingly, it is an object of the invention to provide a precise positioning operation. Another object of the invention is to ensure guidance when the rod is being translated.